Many technological improvements in window and door design have been made available over the last several years. For instance, the insulating properties of newer window constructions are greatly improved over older window constructions, which can often provide significant energy cost savings to property owners. Consequently, a significant need has developed for replacing windows and doors during remodeling of older homes and buildings with newer, more efficient components.
However, most conventional windows, doors, patio doors, etc. are currently built to standardized dimensions. Since different sizes of windows and doors require differently sized components, it is common practice for manufacturers to offer only a limited number of standardized sizes of windows and doors, which reduces the overall manufacturing complexity and cost of these structures based upon the efficiencies obtained through economies of scale.
Many older windows and doors do not conform to standard sizings, and often it is difficult to find replacement windows which exactly fit the rough-in dimensions of a window or door to be replaced. Therefore, since standard sizes of windows and doors are often not acceptable substitutes as replacement windows, some replacement applications may require custom built windows or doors, which typically require individual components to be separately manufactured to size. Consequently, custom window construction often does not obtain the benefits of economies of scale, e.g., high volume production of structures using standardized parts. Thus, many custom windows and doors are significantly more expensive than their standardized counterparts.
Therefore, a need exists for a modular system for manufacturing windows and doors of custom sizes and shapes which offers less complex and expensive manufacture of structures such as windows and doors. In particular, such a need exists for replacement applications where standardized components are often not compatible.
A need has also developed for improved joint structures for joining framing components such as used for window sashes, window frames, door frames, etc. For example, windows typically require joint structures for sashes which are used to retain a window glass assembly within a frame. A window glass assembly is typically a single pane of glass, or alternately, a self-contained multi-paned insulated glass unit whereby two or more panes are stacked and sealed about their perimeters, with a partial vacuum and/or an insulating gas such as argon disposed in the sealed spaced between panes.
Generally, a sash used to retain a window glass assembly includes framing components which are generally L-shaped in cross-section. A silicone sealant is layered along the inside of the frame, and then the window glass assembly is placed in the frame against the silicone sealant. A glazing bead is then installed around the open side of the sash to retain the window glass assembly therein.
It is also known to include spacer blocks sandwiched between the edges of the window glass assembly and the L-shaped channel in the sash, which forms a condensation channel and centers the pane in the sash. Further, by constructing the sash members of a heat weldable plastic, it is known that custom sashes may be constructed by miter cutting individual sash members to size, then butt welding the mitered ends of the sash members together.
However, there are several drawbacks to this type of construction. First, curing of the silicone sealant often adds significant delays to the manufacturing process. Typically, the sealant must cure at least 20 minutes before the sash and window glass assembly may be handled since the window glass assembly is not adequately held within the sash until the sealant at least partially cures. Furthermore, the assemblies typically may not be shipped until the sealant has fully cured, which may take up to eight hours or more. Second, installation of the glazing bead requires an additional manufacturing step, as well as an additional component, which increases the complexity and cost of the custom constructions.
One process which offers improved performance over many conventional custom construction processes is disclosed in German Application No. 3318684 A1.
The German reference generally discloses a sash having a plurality of grooved sash members which include U-shaped glass receiving channels that receive and support the window glass assembly therein. The individual sash members are formed of a preformed plastic which is compatible with heat welding. Each of the sash members is miter cut at a 45.degree. angle, then the sash members and window glass assembly are arranged generally in a plane with the sash members oriented around the periphery of the assembly. Next, individual heating platens are interposed between the mitered edges of the sash members, and the members are forced against the heating platens to heat and plasticize the mitered edges. The sash members and platens are next withdrawn, and then the sash members are forced together under pressure with the window glass assembly retained within the glass receiving channels thereof until the plasticized mitered edges are heat welded to one another. Finally, a silicone adhesive sealant is applied to both sides of the glass receiving channels to provide an air and water seal for the window as well as to secure the window glass assembly in place in the sash.
Several advantages are obtained by the process disclosed in the German reference. For example, the completed sash and window glass assembly may typically be handled immediately after the heat welding operation, as well as after the silicone adhesive is applied, since the window glass assembly is sufficiently held in place within the glass receiving channels even prior to curing of the adhesive. Furthermore, the glazing bead is no longer used or needed. Consequently, there are significant savings in cost and manufacturability offered by the German process.
Several drawbacks nonetheless exist with the German process. First, the manufactured sashes often don't have the same decorative appearance of many older windows. In particular, many older wood frame windows utilize mortise and tenon joint structures. In windows with mortise and tenon joint structures, vertically extending stile sash members are joined to horizontally extending rail sash members. At each joint, one of the members includes a flange disposed at its end, and the other member includes an aperture formed on a side surface thereof for receiving the flange. The appearance of the mortise and tenon joint structure is defined by the squared edge extending across one of the members.
The aforementioned German process, on the other hand, produces sashes with mitered joints. Since many older windows utilize other joint structures, any replacement windows constructed with the German process would not precisely match the windows which were replaced. Further, if only a few of the windows in a building were replaced, the replacement windows would not match the remaining windows in the building.
Second, heat welding a plastic material to form the joints between sash members typically creates flashing which diminishes the decorative appearance of the joint. Often, the flashing is removed along the mating surface between the members. However, it is often difficult to remove all of the flashing material from the decorative surfaces of the sash. The German process attempts to reduce the amount of flashing by providing bevels along the mitered surfaces. However, some amount of flashing will typically still be formed along the opposing decorative surfaces of the sash.
Therefore, there is a need in the art for a window assembly process whereby sash members may be assembled around a window glass assembly in a faster, less expensive, and less complex manner, while having improved decorative appearance. Furthermore, there is a need for a window assembly process which may utilize different styles of architectural or decorative joint structures, in particular so that a replacement window may be constructed having a similar architectural style as that of the replaced window.